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sarongsong
2004-Feb-16, 11:29 PM
"...Venus passes directly between the Earth and the sun June 8...will last about six hours...a little dot that just gradually moves across the sun...the last time one occurred was 1882...The next Transit of Venus will happen in 2012..."
http://makeashorterlink.com/?J5CE13A67

Maksutov
2004-Feb-17, 03:28 AM
"...Venus passes directly between the Earth and the sun June 8...will last about six hours...a little dot that just gradually moves across the sun...the last time one occurred was 1882...The next Transit of Venus will happen in 2012..."
http://makeashorterlink.com/?J5CE13A67

It's never too early to remind folks that are new to observing Sun-related events: NEVER look directly at the Sun. NEVER look at the Sun through any kind of optical equipment. You can PERMANENTLY damage your eyes. :roll:

I've found that for eclipses and transits, using my RFT with a white board projection system works like a charm, and the large image on the screen can be enjoyed by many persons at once.

I know the article had a similar warning, but it was buried at the bottom, and was almost like an afterthought.

milli360
2004-Feb-17, 10:31 AM
It's never too early to remind folks that are new to observing Sun-related events: NEVER look directly at the Sun. NEVER look at the Sun through any kind of optical equipment. You can PERMANENTLY damage your eyes.
There are safe solar filters for optical equipment though.


I've found that for eclipses and transits, using my RFT with a white board projection system works like a charm, and the large image on the screen can be enjoyed by many persons at once.
We've done that many times, but we've noticed that with a large scope and the highly reflective white board, there can be an image (of the eyepiece) returned that may be harmful.

kucharek
2004-Feb-17, 11:02 AM
Here is more technical data on the transit:
http://sunearth.gsfc.nasa.gov/eclipse/transit/TV2004.html

And it is completely visible in Old Europe ;-)

I already submitted a "cancel on short notice" day off to my boss. That means, if the weather is lousy, I'll go to work. If the weather is fine, I'll go to watch that event.

Harald

kucharek
2004-Feb-17, 11:03 AM
There are safe solar filters for optical equipment though.

But only if you know how to handle that equipment. Just think about someone put a filter at his scope which suddenly comes off or something like this.

milli360
2004-Feb-17, 11:13 AM
There are safe solar filters for optical equipment though.

But only if you know how to handle that equipment.
That's true of any specialized equipment. But someone operating a telescope with an appropriate solar filter can offer views to the general public with no fear of problems.

Mainframes
2004-Feb-17, 05:50 PM
Anyone got links to sites that sell the solar filter material? Uk based that is!

calliarcale
2004-Feb-17, 06:12 PM
Anyone got links to sites that sell the solar filter material? Uk based that is!

I'm not sure if they ship to the UK, but you can try Orion Telescopes and Binoculars (http://www.telescope.com). They sell objective filters (filters that fit to the end of your telescope).

SarahMc
2004-Feb-17, 06:13 PM
Anyone got links to sites that sell the solar filter material? Uk based that is!

http://www.baader-planetarium.com/sofifolie/sofi_start_e.htm

You can get it here from the source, Baader Planetarium, although it's in Germany. I'd be very surprised if they don't sell it in the UK as well.

jfribrg
2004-Feb-17, 06:48 PM
Is it necessary to use a telescope? I have a pair of solar glasses that were inserted into an issue of Sky and Telescope magazine. They work great for eclipses, but not for sunspots. What magnification would be necessary? Not that anyone has first hand experience with transits of Venus, but I figured I'd ask anyway. While I'm at it, when is the next transit of Mercury and what magnification is necessary for that?

Mainframes
2004-Feb-17, 07:06 PM
Cheers for those links!

Astronot
2004-Feb-17, 07:21 PM
Boo! Hoo! Here in the Space City we will only see the last few minutes after egress has already begun.

aurora
2004-Feb-17, 07:32 PM
Is it necessary to use a telescope? I have a pair of solar glasses that were inserted into an issue of Sky and Telescope magazine. They work great for eclipses, but not for sunspots. What magnification would be necessary? Not that anyone has first hand experience with transits of Venus, but I figured I'd ask anyway. While I'm at it, when is the next transit of Mercury and what magnification is necessary for that?

Mercury is very tiny against the disk of the sun, certainly not visible without magnification. You really need a pretty good telescope to observe a Mercury transit well.

Venus will only be little larger, I don't think anyone would be able to observe it naked eye (looking through a solar filter, of course).

Maybe projection would show the small black dot.

Maksutov
2004-Feb-18, 04:30 AM
It's never too early to remind folks that are new to observing Sun-related events: NEVER look directly at the Sun. NEVER look at the Sun through any kind of optical equipment. You can PERMANENTLY damage your eyes.
There are safe solar filters for optical equipment though.

I'm with kucharek though. You never know if someone's going to bump the scope or if the filter's going to crack, and, meanwhile, your eye is in the direct axis of the focused solar image. Ouch! I prefer indirect solar viewing at all times.



I've found that for eclipses and transits, using my RFT with a white board projection system works like a charm, and the large image on the screen can be enjoyed by many persons at once.
We've done that many times, but we've noticed that with a large scope and the highly reflective white board, there can be an image (of the eyepiece) returned that may be harmful.

That's why I use my 4.25" RFT. There's never enough heat at any point of focus on an object to cause problems. But the image sizes and resolution get the job done for eclipses and transits. In fact, many owners of large scopes stop their apertures down to achieve these same objectives.

If the 'scope's just being used for photography, I can see using filters.

hewhocaves
2004-Feb-18, 04:37 AM
*sigh* guess it's time to start saving up for the solar filter. darn those inner planets! can't they watch where they're going??

hey, i wonder if anyone is doing some 'practice tests' to try and detect any venusian atmosphere to compare against extrasolar techniques. Seems to me an excellnet time to give some new technique a try.

Mainframes
2004-Feb-20, 06:39 PM
For all those in the UK, David Hinds do double coated mylar film safe for use with telescopic equipment. Only 15.50 inc. P&P for an A4 sheet.

www.dhinds.co.uk

Going to order some for myself asap!